The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
IEEE sections 802.11, 802.11(a), 802.11(b), 802.11(g), 802.11(h), and 802.11(n) (collectively IEEE section 802.11), which are hereby incorporated by reference in their entirety, define ways for configuring wireless Ethernet networks and devices. According to IEEE section 802.11, wireless Ethernet network devices (hereinafter devices) may operate in an ad-hoc mode or an infrastructure mode.
Referring now to FIGS. 1 and 2, wireless Ethernet networks comprising devices communicating in ad-hoc and infrastructure modes are shown, respectively. In ad-hoc mode, each client station 10-1, 10-2, . . . , and 10-N (collectively client stations 10) communicates directly with other client stations without requiring an access point (AP). In infrastructure mode, each client station 20-1, 20-2, . . . , and 20-M (collectively client stations 20) communicates with other client stations through an AP 24. The AP 24 may provide a connection to a network 26, a server 28, and for the Internet 30.
Referring now to FIG. 3, the AP 24 transmits beacons at a programmable beacon interval. Every Nth beacon is a delivery traffic indication message (DTIM) beacon, where N is an integer greater than or equal to 1. The AP 24 transmits DTIM beacons at a DTIM beacon interval, where the DTIM beacon interval is equal to N beacon intervals. The DTIM beacon is followed by buffered broadcast and multicast frames transmitted by the AP 24 to the client stations 20.
Generally, the AP 24 and the client stations 20 do not exchange data at all times. Accordingly, client stations 20 may operate in two modes: an active mode and a low power or standby mode called a power save mode. When the AP 24 and the client stations 20 exchange data, the client stations 20 may operate in the active mode. On the other hand, when the AP 24 and the client stations 20 do not exchange data, the client stations 20 may operate in the power save mode to conserve power. Based on the DTIM beacon interval, the client stations 20 may determine the duration of time to remain in the power save mode before waking up to receive a next DTIM beacon.
Referring now to FIG. 4, power save modes provided by IEEE section 802.11 include legacy power save and unscheduled automatic power save delivery (UAPSD) modes. When operating in the UAPSD power save mode, the client stations 20 may transition from power save mode to active mode and back to power save mode during one or more service periods (SPs) in the DTIM beacon interval before waking up to receive the next DTIM beacon.
Referring now to FIG. 5, a wireless Ethernet network device 31 (e.g., the client station 20) may be implemented by a system-on-chip (SOC) circuit 40. Typically, the SOC 40 includes one or more processors 42 (e.g., an advanced RISC machine (ARM) processor), a medium access controller (MAC) device 44, a baseband processor (BBP) 46, and a host interface (e.g., a peripheral component interface (PCI)) (not shown). The SOC 40 may communicate with a radio frequency (RF) transceiver 48. In some implementations, the SOC 40 may include the RF transceiver 48. The transceiver 48 communicates with an antenna 49. The wireless Ethernet network device (hereinafter device) 31 transmits and receives data to and from other devices via the RF transceiver 48 and the antenna 49.
The MAC device 44 selects the mode of operation of the BBP 46 and the RF transceiver 48. For example, when the device 31 exchanges data with other devices, the MAC device 44 may instruct the BBP 46 and the RF transceiver 48 to operate in the active mode. On the other hand, when the device 31 does not exchange data with other devices, the MAC device 44 may instruct the BBP 46 and the RF transceiver 48 to operate in the power save mode to conserve power.